摘要:

Populations in which the age of individuals is distributed with respect to time will have only a portion of their numbers subject to sampling at any point in time by any method which does not sample all age classes. An estimate of the total seasonal incidence of a population can be made from a single population density estimate by considering some of the theoretical factors affecting the proportion of the whole population which is counted under such circumstances. In particular, the width of the sampleable age class, the timing of the sample with respect to the frequency distribution of the sample able stages, and the variance of the sampleable age class with respect to time were considered.As a particular example, one method of using this theory is applied to cereal leaf beetle {Oulema melanopus(L.)} populations.

ISSN:1754-5692    

DOI:10.1093/ee/6.1.174

出版商:Oxford University Press    

年代:1977

数据来源: OUP

摘要:

We studied low temperature acclimation by 4 immature age groups (21–24, 14–17, 7–10 or 0–3 days after oviposition), by adults from laboratory-cultured strains, and by a field strain of each of 3 species:Sitophilus oryzae(L.), rice weevil;Sitophilus granarius(L.), granary weevil; andRhyzopertha dominica(F.), lesser grain borer. Insects were acclimated for 3 days at 21.1, 7 days at 15.5 and 7 days at 10.0°C, then placed in 4.4°C 2, 4, or 6 weeks. Non-acclimated samples were placed directly in 4.4°C.Prior acclimation increased survival of all insects at 4.4°C. The most cold-tolerant rice weevils and granary weevils were those of 14–17 days development, and most tolerant lesser grain borers, of 21–24 days. More granary weevil adults from the field strain than from the laboratory strain survived. Granary weevil adults (field or lab) were more cold-tolerant than adults of the other 2 species. The least cold-tolerant stages of all species were 0–3 days development (eggs).

ISSN:1754-5692    

DOI:10.1093/ee/6.1.181

出版商:Oxford University Press    

年代:1977

数据来源: OUP